1. Field of the Invention
The present invention relates to techniques for communicating signals between electronic circuits. More specifically, the present invention relates to techniques for maintaining a DC-voltage level when communicating on-chip signals using capacitively coupled drivers.
2. Related Art
Communicating data over long on-chip signal lines or wires (also referred to as links) at high data rates in a communication channel consumes a significant portion of the total energy used by modern integrated circuit chips. Existing approaches to address this power-consumption problem include using capacitively coupled transmit drivers, which consume power when transmissions occur in transmitted signals.
However, there are limits to the performance improvement offered by this communication technique. For example, existing capacitively coupled transmit drivers block the DC-voltage level of the transmitted signals. As a consequence, if a signal is held or maintained for a sufficiently long period of time then the signal at the end of the line may leak away and cause errors.
A variety of DC-biasing techniques have been proposed to address this problem, including periodically refreshing the DC-voltage level and continuously averaging the DC-voltage level to generate a DC-balanced signal. While these techniques can establish a DC-voltage level, they may increase circuit complexity, power consumption, cost, and/or reduce the effective bandwidth of the communication channel. For example, delays may occur when the communication channel is taken off-line to refresh its DC-voltage level or when signals that are sent through the communication channel are encoded and decoded.
What is needed is a method and an apparatus that facilitates communicating on-chip signals using capacitively coupled drivers without the problems listed above.